Method and apparatus for winding field coils for dynamo-electric machines

ABSTRACT

An apparatus is provided for forming field coils on a stator stack including a plurality of slots defined by stator teeth. The apparatus includes a stator nest for holding a stator stack and a winding tool extending through the stator nest for locating wire in the stator stack. The winding tool includes a wire feed aperture for feeding wire into slots of the stator stack. A drifting tool is supported on the winding tool and includes radially extending drift blades for extending into the slots of the stator stack for forming or shaping wire coils that are wound on the stator teeth by the winding tool. Longitudinal movement of the winding tool causes the drifting tool to move into and out of engagement with the stator stack.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/111,033, filed Apr. 21, 2005, which claims the benefit ofU.S. Provisional Application No. 60/565,324, filed Apr. 26, 2004, bothof which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to stator winding and, moreparticularly, to an apparatus and method for forming wound coils onstator stacks for dynamo-electric machines.

2. Description of the Prior Art

Field winding coils for stators are generally placed on the radiallyinwardly extending teeth of a stator stack by either pre-forming thecoils and then pressing the pre-formed coils over the stator stackteeth, or by winding the coils directly onto the stator stack teeth. Inthe process where the coils are pre-formed, the coils are pushed ontothe stator stack by a coil pusher which forcibly pushes the coils overthe teeth of the stator stack, and a forming tool, or forming tools, maybe provided to shape the wire in the stator stack slots and around theends of the teeth in order to compactly position the coils on the statorstack. In such a construction, excess wire must be provided for thepre-formed coils in order to accommodate the necessary distortions ofthe coils as they are pressed over and around the stator stack teeth.Accordingly, such a construction has been found to provide aninefficient amount of wire, as well as result in a larger statordimension as a result of the excess coil wire extending around the endfaces of the teeth for the stator.

In the alternative construction for field winding, wire is fed from awinding spindle or winding tool directly onto a stator stack wherein thewire is successively wound around the stator stack teeth, and theefficiency of the winding operation is substantially dependent upon theability to direct the wire to desired locations on the teeth as it isfed from the winding spindle. Such a device for feeding wire onto thestator stack to form the coils directly thereon is disclosed in U.S.Pat. No. 6,616,082.

When the wire being wound into the stator stack slots is of a relativelythick gauge, particular problems arise in the feeding and formation ofwire coils on the teeth of the stator stack. In particular, such thickgauge wire does not typically readily conform to the contour of the slotsuch that the slot fill provided by thick gauge wire may be reducedrelative to thinner more flexible gauges of wire.

Further, a winding operation in which pairs of wires are wound into thesame slot simultaneously introduces additional difficulties notaddressed by prior art machines in that the position of each wire in thepairs of wires must be properly coordinated relative to each other inorder to ensure sufficient space for all required windings. Thedifficulty of providing efficient placement of wires is compounded whenmultiple sets or pairs of wires are placed in the stator stacksimultaneously.

In addition, it has been observed that an additional area forimprovement in the winding operation relates to a wire forming operationperformed on wire placed within the slots of the stator stack.Specifically, it is known to move a forming tool having radiallyextending blades into one end of the stator stack for the blades to formthe wire toward the respective stator stack teeth around which the wireis wound. For example, the forming tool may be provided with an actuatorfor moving the forming tool in synchronism with the winding tool. Thatis, the forming tool may move into the stator stack as the winding toolis moved in a direction out of the stator stack. Typically, an endportion of the winding tool closest to the forming tool remains withinor closely adjacent to the end of the stator stack, limiting the abilityof the forming tool to approach that end of the stator stack.Accordingly, in such a winding system, at least a portion of the woundwire may not be formed within the stator stack slots.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, an apparatus is providedfor forming field coils on a stator stack including a plurality of slotsdefined by stator teeth. The apparatus comprises a stator nest forholding a stator stack and a winding tool extending through the statornest for locating wire in the stator stack. The winding tool includes awire feed aperture for feeding wire into slots of the stator stack. Adrift tool is supported on the winding tool and comprises at least oneradially extending drift blade for extending into the slots of thestator stack.

In accordance with another aspect of the invention, an apparatus isprovided for forming field coils on a stator stack including a pluralityof slots defined by stator teeth. The apparatus comprises a stator nestfor holding a stator stack and a winding tool extending through thestator nest for locating wire in the stator stack. The winding toolincludes a wire feed aperture for feeding wire into slots of a statorstack supported in the stator nest. A drift tool is supported on thewinding tool for engaging and forming wire located in the slots of thestator stack.

In accordance with a further aspect of the invention, an apparatus isprovided for forming field coils on a stator stack including a pluralityof slots defined by stator teeth. The apparatus comprises a stator nestfor holding a stator stack and a winding tool extending through thestator nest for locating wire in the stator stack. The winding tool issupported for longitudinal movement and includes a wire feed aperturefor feeding wire into slots of a stator stack supported in the statornest. An upper drift tool is located for engaging and forming wirelocated in the slots of the stator stack adjacent an upper end of thewinding tool, and a lower drift tool is supported for longitudinalmovement with the winding tool for engaging and forming wire located inthe slots of the stator stack adjacent a lower end of the winding tool.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the present invention, it is believed that thepresent invention will be better understood from the followingdescription in conjunction with the accompanying Drawing Figures, inwhich like reference numerals identify like elements, and wherein:

FIG. 1 is an elevation view illustrating a winding machine constructedin accordance with the present invention;

FIG. 2 is a plan view of the winding machine shown in FIG. 1 with thedrifting tool assembly and the linear actuator for the wire clampremoved;

FIG. 3 is a perspective view of a wire supply and wire stripper stationof the winding machine in FIG. 1;

FIG. 4 is a perspective view of a stripper head for a wire stripperassembly;

FIG. 5 is an enlarged view of the stripper head shown in FIG. 4 with astripper head cover and guide bar removed;

FIG. 5A is a perspective view of a movable blade for the stripper headshown in FIG. 4;

FIG. 6 is an exploded view of the stripper head shown in FIG. 4;

FIG. 7 is a perspective view illustrating a pair of upper and lowerstripper assemblies;

FIG. 8 is a perspective view of a wire feed mechanism for the windingmachine in FIG. 1;

FIG. 9 is a perspective view including the wire feed mechanism, aflexible wire guide tube, and a winding tool;

FIG. 10 is a cross-sectional view taken through the wire guide tube;

FIG. 11 is a perspective view of the winding tool;

FIG. 12 is an exploded perspective view from a rear side of the windingtool;

FIG. 13 is an exploded perspective view from a front side of the windingtool;

FIG. 14 is a perspective view of a winding station for the windingmachine in FIG. 1;

FIGS. 15 and 16 are perspective views of a stator nest for the windingstation;

FIGS. 17 and 18 are perspective views of a twisting assembly for thewinding station;

FIG. 19 is a plan view of gripper portion of the twisting assembly;

FIGS. 20-28 are diagrammatic elevation views illustrating the operationof one of the twisting assemblies for the winding station;

FIG. 29 is a perspective view of a robot for loading stator stacks inthe stator nest and for cutting leads on the stators during the windingoperation;

FIG. 30 is a side elevation view, with the stator nest partiallycut-away, showing an alternative embodiment of a winding tool includinga lower drifting tool mounted to the winding tool, where the windingtool is in a lower position of its travel;

FIG. 31 is a side elevation view similar to FIG. 30, where the windingtool is in an upper position of its travel; and

FIG. 32 is a lower perspective view, with the stator nest and lowerdrifting tool partially cut-away, showing the winding tool in a lowerposition of its travel.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, the apparatus of the present inventioncomprises a wire supply 10, a stripper station 12 a feed mechanism orfeeder 14 and a winding station 16. The operation of the apparatusgenerally includes the feeder 14 exerting a tension on wire 18 from thewire supply 10 to draw wire 18 from the wire supply 10 and push or feedit into the winding station 16. As the wire 18 is drawn through thestripper station 12, insulation is stripped from the wire 18 atpredetermined locations along the length of the wire 18. In the windingstation 16, the wire 18 is wound onto a stator stack 208 (FIG. 14) in apredetermined pattern around teeth of the stator stack. It should benoted that the wire of the embodiment being described herein ispreferably 15 gauge (1.45 mm) wire, although the present apparatus maybe used with other thickness or gauge of wire, i.e., the wire may bethicker or thinner.

Referring additionally to FIG. 3, six spools 20 a, 20 b, 22 a, 22 b, 24a, 24 b of wire 18 are provided at the wire supply 10, where the wire 18from each of the spools 20 a, 20 b, 22 a, 22 b, 24 a, 24 b is guided torespective stripper assemblies 26 a, 26 b, 28 a, 28 b, 30 a, 30 b in thestripper station 12 by wire guide structures 32, 34, 36.

Referring to FIGS. 4, 5, 6 and 7, each of the stripper assemblies 26 a,26 b, 28 a, 28 b, 30 a, 30 b includes a stripper head 38 for strippingpredetermined sections of insulation at the predetermined locationsalong the length of the wire 18, under control of a controller (notshown) for the apparatus. The illustrated stripper head 38 correspondsto one of the lower stripper assemblies, i.e., one of stripperassemblies 26 b, 28 b, 30 b, and comprises a stripper housing 40supported on a backing plate 42 and including gear tooth sections 44, 46keyed to the stripper housing for engaging drive belts 48, 50 (FIG. 7).It should be noted that the upper stripper assemblies 26 a, 28 a, 30 aare of the same general construction with the exception that only onegear tooth section 44 is provided. A drive gear 52 of a drive motor 54,i.e., a servo motor, is engaged by the belt 50 for engaging and drivingthe gear tooth section 46 of the illustrated stripper head 38 inrotating movement. The belt 48 is engaged with the gear tooth section 44of the illustrated stripper head 38 and further engages and drives thegear tooth section of the associated stripper assembly, i.e., one ofassemblies 26 a, 28 a, 30 a, in rotation.

The stripper housing 40 includes a slot 56 (FIG. 6) receiving astationary cam plate 58 having an angled first camming surface 60. Thestationary cam plate 58 is held in position by a pair of fasteners 62.In addition, a stop plate 64 is mounted to the stripper housing 40 andis held in place by fasteners 66.

A stripper spindle 68 is positioned extending into a central aperture 70of the housing 40 and is attached to an actuation shaft 72 which isactuated in reciprocating movement by an air actuated collet closer 74,such as an air collet closer manufactured by Dunham Tool Company of NewFairfield, Conn. The stripper spindle 68 includes a slot area 80 and apair of pins 82 extending into the slot area 80. A movable blade holder84 is positioned in the slot area 80 and includes a pair of elongatedslots 86 engaged with the pins 82. The blade holder 84 is movable in aradial direction toward and away from a central axis 85 passing throughthe stripper housing 40. A pair of compression springs 88 are located toengage and bias the blade holder 84 in a direction away from the centralaxis 85 of the stripper housing 40. The blade holder 84 includes a slot90 for receiving and rigidly holding a movable blade 92. The stripperspindle 68 includes a slot 94 for rigidly holding a stationary saddle 96in facing relationship to the movable blade 92. The movable blade 92includes a V-notch 98 for engaging the outer surface of wire 18 passingthrough the stripper head 38 and moving in the direction of the arrow97, as illustrated in FIG. 5A. The stationary saddle 96 provides asupport surface, i.e., arcuate surface 97, adjacent the central axis 85of the stripper housing 40 defining a pocket for supporting the wire 18at the rotational axis of the stripper head 38, such that the engagementof the movable blade 92 with the wire 18 in the radial direction may beaccurately controlled.

Actuation of the movable blade 92 into and out of engagement with thewire 18 is controlled through controlled axial movement of the actuationshaft 72, where movement causing the stripper spindle 68 to move intothe aperture 70 of the housing 40 causes movement of the blade 92 towardthe saddle 96 as a second camming surface 100 on the blade holder 84moves along the angled surface of the first camming surface 60. Themovement of the stripper spindle 68 back into the aperture is limited bycontact of a set screw 102 with the stop plate 64, where the set screw102 is threaded into a hole 103 and extends out the back of the stripperspindle 68 for engaging the stop plate 64. The stroke of movement forthe stripper spindle 68 may be controlled by adjustment of the set screw102 to thereby accurately adjust the amount that the blade 92 movestoward the saddle 96 and thereby obtain accurate adjustment of theamount of material removed from the wire 18 during a strippingoperation.

A stripper head cover 104 is provided attached to the front of thehousing 40 to cover and facilitate retention of the components held inthe stripper spindle 68, where the cover 104 is held in place byfasteners 107 engaged with the stripper spindle 108. The cover 104includes an aperture 105 for permitting access to adjust the set screw102.

In addition, a guide bar 106 is mounted to the cover 104. The guide bar106 includes an aperture 108 which receives the wire 18 and maintainsalignment of the wire 18 as it passes out of the stripper. In order toremove debris from the wire 18 passing out of the stripper head 38, awire clamp 110 (FIG. 7) having felt engagement surfaces 112 is provided.

Further, the stripper assemblies 26 a, 26 b, 28 a, 28 b, 30 a, 30 b areeach provided with a flexible air conduit 114 which is directed to theexit of the stripper head 38. The air conduits operate to blow airacross the exit of the respective stripper heads 38 to facilitateremoval of any debris remaining from the stripping operation.

As noted previously, the wire is stripped at predetermined sectionsalong the wire 18. In particular, two stripped sections are providedadjacent to each other and spaced from each other by a short length ofunstripped section. The leading stripped section forms the end or finalportion of a wound coil on the stator stack and the following strippedsection is provided to form the beginning of a next coil to be wound onthe stator stack. The stripped sections provide stripped areas of thewound coil ends for electrical connection of the coil wire of the woundstator into a dynamo-electric machine utilizing the stator. In should beunderstood that the collet closer 74 is operated under control of thesystem controller (not shown) in order to move the blade 92 intoengagement with the wire 18 and to actuate the motor 54 to drive thedrive gear 52 in order to rotate the stripper head 38 simultaneouslywith the wire 18 being drawn through the stripper head 38 to strip thesections of wire 18 at the appropriate locations on the wire 18, and todisengage the blade 92 and deactivate the motor 54 when non-strippedsections of the wire 18 are required to be fed.

Referring to FIGS. 8 and 9, wire feed from the wire supply 10 throughthe stripper station 12 and into the winding station 16 is controlled bythe wire feed mechanism 14. The wire feed mechanism 14 is designed tosimultaneously feed six wires 18 while maintaining precise positioningof each of the wires 18. The wire feed mechanism 14 includes an upper orfirst endless segment chain 116 and a lower or second endless segmentchain 118. The first endless segment chain 116 is supported by first andsecond gear members 120, 122 and the second endless segment chain 118 issimilarly supported by first and second gear members 124, 126, such thatelongated runs of the first and second endless segment chains 116, 118are in engagement with each other to form a wire drive nip therebetween.

Each of the endless segment chains 116, 118 comprises a respective chain128, 130 and sets of segments or pads 132, 134 mounted to the chains128, 130. Each set of pads 132, 134 comprises a metal, such as aluminum,backing plate 136, 138 and a resiliently compliant engagement layer 140,142 for engaging the wire 18. In the preferred embodiment, the compliantengagement layer 140 of the first set of pads 132 is formed of 80 ShoreA durometer hardness polyurethane, and the compliant engagement layer142 of the second set of pads 134 is formed of a harder material such as90 Shore A durometer hardness polyurethane. In addition, the compliantengagement layers 142 of the second set of pads 134 are each formed witha wide groove or recessed area 144 for receiving the six wires 18 inside-by-side relationship to maintain a predetermined position of thewires 18 as they pass through the elongated nip. The recessed area 144is formed with a depth which is approximately one-third the diameter ofthe wire 18. Engagement pressure in the elongated nip is maintained byupper and lower pressure members 117, 119 engaging the respectiveendless segment chains 116, 118.

The wires 18 arriving from the stripper station 12 enter an alignmentfixture 146 for positioning the wires 18 in side-by-side relationshipprior to entering the elongated nip of the feed mechanism 14. Thealignment fixture 146 includes an elongated tube portion 148 which has atapered end so that a minimum length of wire extends between the end ofthe elongated tube portion 148 and elongated nip between the endlesssegment chains 116, 118.

The feed mechanism 14 includes a servo motor 150 for driving the endlesssegment chains 116, 118. The servo motor 150 directly drives the firstgear member 120 of the first endless segment chain 116, and a gear 152on the shaft 154 connected to the first gear member 120 is engaged witha gear (not shown) on the shaft 156 connected to the first gear 124 suchthat the first gears 120, 124 and their associated endless segmentchains 116, 118 are simultaneously driven at the same speed. The servomechanism 150 is operated under control of the system controller (notshown) to move the wire 18 in both the forward and reverse directions,as required by the particular step being performed in the process ofwinding a stator.

The wire 18 is fed from the elongated nip of the feed mechanism 14 to anexit tube 158 of a wire exit fixture 160. The exit tube 158 has atapered end to permit positioning of the tube 158 in close proximity tothe nip. An elongated flexible wire guide tube 162 is provided andincludes one end connected to the wire exit fixture 160 and an oppositeend connected to the bottom of a winding tool shaft 164. The guide tube162 guides the wire 18 from the feed mechanism 14 to the interior of thewinding tool shaft 164.

As may be seen in FIG. 10, the flexible wire guide tube 162 is formedwith a generally rectangular outer sleeve 166 defined by an extrudedplastic tube. The wider dimensioned interior sides are each lined withspring steel strips 168. The wire 18 is guided through an interiorpassage 170 of the guide tube 162 in side-by-side relation and thespring steel strips 168 provide a low friction surface for guiding thewire 18. The spring steel strips 168 further provide a resilientrigidity allowing the guide tube 162 to bend along one axis as well aspermitting the guide tube 168 to twist.

The structure supporting the winding tool shaft 164, including theactuation structure for actuating the tool shaft 164 and a winding tool172 located at the top of the tool shaft 164 in movement is disclosed inU.S. Pat. No. 5,964,429. Referring to FIG. 7, the tool shaft 164 andassociated winding tool 172 are actuated for reciprocating movement by adrive rod 173 pivotally connected to a slide block platform 175supporting the tool shaft 164. The drive rod 173 may be driven by aneccentric drive mechanism (not shown) in a known manner. Rotationalmovement of the tool shaft 164 may be obtained by a spindle shaft gear177 driven by a belt 179 engaged around an oscillating gear 181. Theoscillating gear 181 is coupled to a coupler 183 which is slidablyengaged on a splined shaft 185, driven by a servo motor (not shown) tomove the shaft 185 in precise oscillating movement. The splinedengagement between the coupler 183 and the shaft 185 permits slidingmovement of the coupler 183 relative to the shaft 185 while transmittingan oscillating drive movement to the winding tool 172 in a mannerdescribed in U.S. Pat. No. 5,964,429. Specifically, the winding tool 172is moved in generally longitudinal movement as wire is fed through slotsof a stator stack, and the winding tool 172 is rotated at the end ofeach longitudinal stroke to form end turns around the ends of the statorstack as wire is fed from the winding tool, as controlled by the wirefeed mechanism 14. The present invention provides an improvement inlocating the feed mechanism 14 in spaced relation to the reciprocatingcomponents to thereby reduce the weight and provide for increased speedof the moving components in the winding station 16.

Referring to FIGS. 11, 12 and 13, the winding tool 172 includes a toolbase 174 and a wire guide insert member 176 attached to a side portionof the tool base 174. The tool base 174 includes an indentation area 178which angles radially outwardly from a generally central wire entrylocation 180 at the bottom of the tool base 174 toward one side at anupper area 182, and the upper area 182 is curved in a radial directionback toward the opposite side of the tool 172. The outward angle of theindentation area 178 and the curvature of the upper area 182 areprovided to permit the wire 18 to pass centrally out of the tool shaft164 and follow a sufficiently broad radius of curvature to reduce anybending required of the wire 18 as it passes up through the winding tool172.

The wire guide insert member 176 includes an engagement surface 184 forengaging with the surface of the indentation area 178 and includinggrooves 186, 188, 190 defined in the engagement surface 184 for guidingwire 18 to respective exit apertures 192, 194, 196. The exit apertures192, 194, 196 are vertically elongated apertures which are defined byelongated angled slots 193, 195, 197, an insert sector 198, and bygrooves 199, 201, 203 in an upper outer edge 200 of the outwardly curvedupper area 182, where the slots 193, 195, 197 are angled at the sameangle as a skew angle of the slots defined in the stator stack 208 to bewound. The grooves 186, 188, 190 function in a manner similar to thatdescribed for the winding tool grooves in U.S. Pat. No. 6,616,082, wherethe entrance to the grooves 186, 188, 190 of the winding tool 172 areconfigured to guide the wire 18 into the grooves 186, 188, 190 as thewire is threaded up into the winding tool 172 from the tool shaft 164,such that the winding tool 172 is self threading. However, in thepresent tool 172, a pair of wires 18 is threaded into each of thegrooves 186, 188, 190, where the pairs of wires 18 are orientedvertically within the grooves 186, 188, 190, and the angle of the slots193, 195, 197 positions the vertically oriented wires at an anglesubstantially matching the angle of the slots between teeth of thestator stack 208. Further, each pair of wires guided through one of thethree grooves 186, 188, 190 is drawn through a corresponding one of thepairs of wire stripper assemblies 26 a, 26 b; 28 a, 28 b; 30 a, 30 b. Inaccordance with the present invention, the wires 18 exiting eachaperture 192, 194, 196 of the winding tool 172 are wound in the statorstack as wire pairs, rather than as single strands of wire.

It should be noted that the insert sector 198 may be replaced with aninsert sector having slots oriented a different angle, and thus mayaccommodate use of the winding tool 172 to wind coils on stator stackshaving slots formed at different angles.

As with the winding tool disclosed in U.S. Pat. No. 6,616,082, the topof the winding tool 172 includes an alignment shaft 202. The alignmentshaft 202 engages with a cooperating aperture in the bottom of an upperdrifter or drifting tool 204 (FIG. 14) to maintain alignment between thewinding tool 172 and the drifting tool 204 during a winding operation.

Referring to FIG. 14, the components of the winding station 16 forperforming the coil winding operation are substantially the same asthose described in U.S. Pat. No. 6,616,082, and in U.S. Pat. No.6,206,319, which discloses a lower wire clamp as used in the apparatusdisclosed in U.S. Pat. No. 6,616,082. Generally, the winding station 16includes a stator nest 206 for holding a stator stack 208 to be wound,and through which the winding tool 172 passes in reciprocating androtating movement. The upper drifting tool 204 is supported forreciprocating movement with the winding tool 172 by drifting toolassembly 210 and is actuated in rotating movement by a servo motordriven actuator 212. In addition, an upper wire clamp 214 is supportedfor vertical reciprocating movement by a linear actuator 216.

Referring further to FIGS. 15 and 16, the stator nest 206 comprises abase ring 218 for receiving a stator stack 208, where the stator stack208 may be deposited in the base ring 218 by a stator holder 219 locatedon a movable extension 221 of a robotic apparatus 220 (FIGS. 2 and 29)such as a Denso VS-6556EM. The base ring 218 includes a lower radiallyinwardly extending lip for supporting the stator stack 208. A pair ofclamp arms 222, 224 are supported for pivotal movement, as actuated byactuator assemblies 226, 228, such as air actuated assemblies to moveinto close engaging contact with the stator stack 208. In addition, theactuator assemblies 226, 228 actuate the clamp arms 222, 224 to movevertically downwardly as they pivot, such that they each travel in ahelical path as they pivot. The actuator assemblies 226, 228 maycomprise an SC series swing clamp provided by Numatics Motion Control ofAvon, Ohio. Guide posts 230, 232 attached to respective clamp arms 222,224 move through slots 234, 236 to guide and support the clamp arms 222,224 in their movement. The clamp arms 222, 224 meet in their closingmovement at a location slightly vertically spaced above their finalposition. In a final step of clamping the stator stack 208, the clamparms 222, 224 are moved in linear vertical movement to engage an upperradially inwardly extending lip defined by upper edges of the clamp arms222, 224 to firmly clamp the stator stack 208 between the base ring 218and the clamp arms 222, 224.

As seen in FIG. 14, the winding station 16 further includes threetwisting assemblies 238, 240, 242 aligned at predetermined locationsrelative to the stator nest 206 and the stator stack 208 held therein,as well as relative to the position of the winding tool 172 at thebeginning and end of a winding operation. As is described in greaterdetail below, each of the twisting assemblies 238, 240, 242 arepositioned at locations aligned with the wire exit apertures 192, 194,196 of the winding tool 172 in order to grip and rotate or twist therespective pairs of wires 18, extending from the winding tool 172 at thebeginning of a winding operation and extending from a completed coil onthe stator stack 208 at the end of a winding operation.

Referring to FIGS. 17, 18 and 19, the structure of the twistingassemblies will be described with particular reference to one of thetwisting assemblies 238, the other twisting assemblies 240, 242 beingidentical. The twisting assembly 238 includes a vertical actuatorsubassembly 244, a horizontal actuator subassembly 246 and a grippersubassembly 248. The horizontal actuator subassembly 246 is supported bythe vertical actuator subassembly 244 for movement in a verticaldirection between predetermined upper and lower positions. The grippersubassembly 248 is supported by the horizontal actuator subassembly 246for movement in the horizontal direction, and the gripper subassembly248 includes a gripper portion 250 which is actuated for rotationalmovement.

The vertical actuator subassembly 244 includes a pair of support posts256, 258 and a pair of bearing blocks 260, 262 supported on the supportposts 256, 258 for sliding movement. The bearing blocks 260, 262 areactuated in vertical movement by an air cylinder actuator 264. Thetravel of the bearing blocks 260, 262 is limited by respective pairs ofupper and lower stops 266, 268 and 270, 272. In addition, the verticalposition of the bearing blocks 260, 262 is monitored by upper and lowersensors 274, 276.

The horizontal actuator subassembly 246 includes a support plate 278supported on the bearing blocks 260, 262 of the vertical actuatorsubassembly 244. The support plate 278 supports a pair of guide rods280, 282, and a pair of bearing blocks 284, 286 are supported on theguide rods 280, 282 for sliding movement. An air cylinder 288 issupported on the support plate 278 for providing a biasing force andmoving the bearing blocks 284, 286 along the guide rods 280, 282. Inaddition, the horizontal position of the bearing blocks 284, 286 at aplurality of predetermined locations is monitored by sensors 290, 292,294, 296.

The gripper subassembly 248 is supported on the bearing blocks 284, 286of the horizontal actuator subassembly 246 and includes a rotation servomotor 298 and an air driven grip actuator 300. The servo motor 298 andgrip actuator 300 operate to cause rotating and gripping movement of thegripper portion 250. As seen in FIG. 19, the gripper portion 250comprises a pair of grip jaws 302, 304 which are actuated between anopen position where the jaws 302, 304 are separated from each other, anda closed position where the ends of the jaws 302, 304 are in grippingengagement adjacent each other. The rotation servo motor 298 operates torotate the jaws 302, 304 about a rotation axis 306 for the jaws 302, 304to perform a twisting operation on wire 18, such as pairs of wire 18,gripped by the ends of the jaws 302, 304. In addition, it should benoted that a space 308 is defined between the closed jaws 302, 304 whichis used for capturing the pairs of wire 18 in sliding contact in a loopforming operation, as will be described further below.

Referring to FIGS. 20-28, showing the twisting assembly 238diagrammatically, the operation of the twisting assemblies 238, 240, 242will be described with reference to the twisting assembly 238, it beingunderstood that similar operations are performed by the twistingassemblies 240, 242 simultaneously with the operation described for thetwisting assembly 238.

At the initiation of a winding operation, as seen in FIG. 20, a leadingend of a pair of the wires 18 are fed by actuation of the feed mechanism14 to extend from the winding tool 172, and the ends of the wires 18 aregripped by the jaws 302, 304. It should be noted that the section of thewires 18 at the gripped ends have been stripped of insulation at thestripping station 12. After gripping the wires 18 adjacent the windingtool 172, the gripper subassembly 248 moves back under actuation of alow pressure applied to the air cylinder 288 (FIG. 21) and the wire isfed out of the winding tool 172 by actuation of the feed mechanism 14.It should be understood that the pressure applied by the air cylinder288 is not sufficient to cause the wire 18 to be drawn out of thewinding tool 172. The pressure applied by the air cylinder 288 issufficient to maintain a tension on the wire 18 and the extent to whichthe wire 18 passes out of the winding tool 172 is controlled throughactuation of the feed mechanism 14.

After pulling the wire 18 back, as dictated by the wire feeder 14, thejaws 302, 304 are rotated to twist the wire pair, as illustrated by FIG.22. In this step, the gripper jaws 302, 304 are substantially at thesame level as the wire exit aperture 192. Subsequently, the winding tool172 performs a coil winding operation in a known manner, as described inthe above-referenced patents, to form wire coils comprising two wiresfor each coil. It should be noted that the low pressure provided by theair cylinder 288 provides a compliant force for holding the wires 18whereby, at the initiation of the winding operation, the jaws 302, 304are permitted to move toward the winding tool 172 in response to aninitial winding force, which movement prevents the wound wire from beingbent sharply and possibly being cut as the winding operation begins.Also, the compliant force avoids slippage of the wire in the jaws 302,304 which could cause damage to the wire and/or loss of gripping contactbetween the jaws 302, 304 and the wire 18. Subsequent to the initiationof the winding operation, the jaws 302, 304 may release the ends of thewire 18.

The twisting assemblies 238, 240, 242 are further used to twist theleads at the end of the winding operation, as is further described withreference to a single twisting assembly 238. Referring to FIG. 23, atthe end of the coil winding operation, the winding tool 172 is locatedat an elevated position, where the wire exit aperture 192 is locatedabove the level of the jaws 302, 304. An amount of wire 18 is fed fromthe winding tool 172 to form a vertically extending loop of wire.

As seen in FIG. 24, the jaws 302, 304 are moved inwardly and closedtogether such that the ends of the jaws 302, 304 meet in a space betweenthe loop of wire 18 and the winding tool 172. The wire 18 extendsthrough and is trapped within the space 308 between the closed jaws 302,304. A low pressure is then applied to the air cylinder 288 and the feedmechanism 14 is activated to feed additional wire 18 from the windingtool 172, such that the jaws 302, 304 move away from the winding tool172, and the loop of wire slides through the space 308 as the loop isexpanded by driving the wire feed mechanism 14 in combination withsimultaneous the movement of the jaws 302, 304 away from the windingtool 172, as seen in FIG. 25.

After the jaws 302, 304 have expanded the wire loop, the pressure in theair cylinder 288 is neutralized, and an additional small amount of wire18 is fed to release tension on the wire loop. The jaws 302, 304 arethen moved downwardly to a position which places the jaws 302, 304substantially level with the top of the stator stack 208 and the top ofthe clamp arms 222, 224, as seen in FIG. 26. The jaws 302, 304 rotateslightly to align the jaws 302, 304 with both of the wire strands, whichare oriented between a vertical and horizontal alignment relative toeach other as a result of extending out of the winding tool 172 andaround the jaws 302, 304 in a loop. The jaws 302, 304 then grip the wire18 at the outer edge of the loop.

As seen in FIG. 27, with the wires gripped by the jaws 302, 304, acutter 310 mounted to the robotic apparatus 220 is moved into alignmentwith an upper portion of the wire loop and cuts the wire 18. Theremaining wire extending from the winding tool 172 is drawn back intothe winding tool 172 by reversing the drive direction of the feedmechanism 14, the winding tool 172 moves down to position the wire exitapertures 192, 194, 196 below the level of the stator nest 206, and thedrifting tool 204 moves down into engagement within the stator stack208, as illustrated in FIG. 28. In addition, the jaws 302, 304, whichcontinue to grip the wire 18 after the wire cutting operation, aredriven in rotation to twist the wires 18 together.

It should be noted that the ends of the wires 18 twisted at the end ofthe coil winding operation have been stripped at the stripper station12, and the ends of the leads remaining extending from the winding toolafter the wire cutting operation are also stripped and will form thestarting leads for the next coil forming operation.

In addition, subsequent to the winding tool 172 moving down below thestator nest 206, the feed mechanism 14 feeds wire forward and thestripper station 12 is activated to perform a stripping operation onsections of the wire 18 resulting in wire 18 being pushed out of thewinding tool 172. Subsequent to the wire stripping operation, the feedmechanism 14 is reversed to draw the wire back into the winding tool 172in preparation for moving the winding tool 172 upwardly to perform thenext coil winding operation when another stator stack 208 is loaded inthe stator nest 206 by the robotic apparatus 220 (FIG. 29).

It should be understood that the wire is stripped in the strippingstation 12 at predetermined locations such that the stripped sections ofthe wire 18 will arrive in the winding tool 172 at the appropriate timesto coincide with the beginning or end of a coil winding.

Also, it should be noted that the movable extension 221 of the roboticapparatus 220 (FIG. 29) is capable being manipulated by the roboticapparatus 220 to position the stator holder 219 and the cutter 310 atthe appropriate location for either transferring a stator stack 208 toor from the stator nest 206, or for cutting the wires 18.

Referring to FIGS. 30-32, an alternative embodiment for a winding tool172′ is illustrated. The winding tool 172′ includes a lower undercut orrecessed circumferential portion 320 (FIG. 32) located below three wirefeed or exit apertures (only two exit apertures 192′, 194′ shown) suchthat an upper ledge 324 is defined on the winding tool 172′ extendingbetween the recessed circumferential portion 320 and an outercircumferential portion 326. A lower ledge 328 is defined by a collar orflange member 330 attached to the winding tool shaft 164 and positionedagainst the base of the winding tool 172′.

A hollow lower drifter or drifting tool 332 is supported on the windingtool 172′ between the upper ledge 324 and the lower ledge 328, andincludes an annular body 333 surrounding the recessed circumferentialportion 320. Both the upper drifting tool 204 and lower drifting tool332 include radially extending blades 334, 336, respectively, forengaging through the slots in the stator stack 208 to form wire coilstherein by pressing the wire toward the teeth of the stator stack 208.The blades 334, 336 are angled along their length relative to thelongitudinal axes of the respective drifting tools 204, 332 forengagement within similarly longitudinally angled slots formed in thestator stack 208. The lower drifting tool 332 is supported to freelyrotate about the winding tool 172′ relative to the upper and lowerledges 324 and 328.

The stator nest 206 is provided with a guide pin 338 mounted on asupport 340 adjacent a lower side of the stator nest 206. The guide pin338 is fixed relative to the stator nest 206 and includes a distal end342 that extends to a location between two adjacent blades 336 of thelower drifting tool 332. The diameter or width of the guide pin 338 issuch that it is closely adjacent to the blades 336 on either side, butsized less than the spacing between the blades 336 such that the guidepin 338 may be in sliding engagement with the blades 336.

The lower drifting tool 332 is movable with the winding tool 172′ in alongitudinal direction as the winding tool 172′ reciprocates into andout of the stator stack 208 during a winding operation. As the driftingtool 332 moves in the longitudinal direction, sliding engagement betweenthe blades 336 and the guide pin 338 will cause the drifting tool 332 torotate on the flange member 330 relative to the winding tool 172′,resulting in the blades 336 following the angled slots in the statorstack 208. Accordingly, the rotational movement of the lower driftingtool 332 will be synchronized with the longitudinal movement of thewinding tool 172′ without requiring an additional driving member such asan additional motor.

FIG. 30 illustrates the winding tool 172′ located at a lower position ofits travel with the upper drifting tool 204 located within the statornest 206 and substantially fully engaged within a stator stack 208, andwith the lower drifting tool 332 positioned below the stator nest 208.FIG. 31 illustrates the winding tool 172′ located at an upper positionof its travel, with the lower drifting tool 332 located within thestator nest 206 and substantially fully engaged within a stator stack208. The guide pin 338 remains engaged between a pair of the lowerdrifting tool blades 336 throughout the longitudinal travel of the lowerdrifting tool 332 to maintain a predetermined alignment between thelower drifting tool 332 and a stator stack 208 located within the statornest 206.

It should be understood that the lower end of the blades 334 of theupper drifting tool 204 and the upper end of the blades 336 of the lowerdrifting tool 332 are each formed with a tapered configuration tofacilitate passage of the blades 334, 336 through the wires formedwithin the stator stack 208. Further, the tapered ends of the blades334, 336 generally do not fully form the wires in stator stack 208 atthe end of travel of the respective drifting tools 204, 332.Accordingly, it has been found to be beneficial to provide both upperand lower drifting tools 204, 332 to ensure that the wound wire coilsare fully formed, i.e., are displaced toward their respective supportingstator teeth, during the process of winding wire into the stator stack208. Specifically, if portions of the wire coils are not fully formedduring movement of the upper drifting tool 204 down through the statorstack 208, e.g., portions of the wire coils closest to the lowerdrifting tool 332, the upward movement of the lower drifting tool 332will cause these portions of the wire coils to be formed. Similarly, ifportions of the wire coils are not fully formed during movement of thelower drifting tool 332 upwardly through the stator stack 208, e.g.,portions of the wire coils closest to the upper drifting tool 204, thedownward movement of the upper drifting tool 204 will cause theseportions of the wire coils to be formed.

All documents cited in the Detailed Description of the Invention areincorporated herein by reference; the citation of any document is not tobe construed as an admission that it is prior art with respect to thepresent invention.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. An apparatus for forming field coils on a stator for adynamo-electric machine, said stator including a plurality of slotsdefined by stator teeth, said apparatus comprising: a stator nest forholding a stator stack; a generally cylindrical winding tool extendingthrough said stator nest for locating wire in a stator stack held insaid stator nest, said winding tool including a wire feed aperture forfeeding wire into slots of a stator stack supported in said stator nest;a drift tool supported on said winding tool, and comprising at least oneradially extending drift blade for extending into the slots of saidstator stack, said drift tool including an annular body: and whereinsaid winding tool includes an undercut portion, and said annular body ofsaid drift tool surrounds said undercut portion.
 2. The apparatus ofclaim 1, including a collar supported on said winding tool, said drifttool being supported between said collar and said wire feed aperture. 3.The apparatus of claim 1, wherein said drift tool is rotatable relativeto said winding tool.
 4. The apparatus of claim 3, wherein said drifttool includes at least two radially extending drift blades for extendingthrough the slots of said stator stack, and including a stationary guidepin located on said stator nest and positioned between said drift bladesto guide said drift tool in rotating movement.
 5. The apparatus of claim1, further including an upper drift tool located adjacent an upper endof said winding tool and comprising at least one radially extendingdrift blade for extending into the slots of said stator stack.
 6. Anapparatus for forming field coils on a stator for a dynamo-electricmachine, said stator including a plurality of slots defined by statorteeth, said apparatus comprising: a stator nest for holding a statorstack; a winding tool extending through said stator nest for locatingwire in a stator stack held in said stator nest, said winding toolincluding a wire feed aperture for feeding wire into slots of a statorstack supported in said stator nest; a lower drift tool supported onsaid winding tool adjacent a lower end of said winding tool, said lowerdrift tool including at least one drift blade for extending through theslots of said stator stack and for engaging and forming wire located inthe slots of said stator stack; and including an upper drift toollocated adjacent an upper end of said winding tool, said upper drifttool including at least one drift blade for extending through the slotsof said stator stack and for engaging and forming wire located in theslots of said stator stack.
 7. The apparatus of claim 6, wherein saidlower drift tool is driven in reciprocating longitudinal movement bysaid winding tool.
 8. The apparatus of claim 7, wherein said lower drifttool rotates in response to the longitudinal movement of said windingtool.
 9. The apparatus of claim 6, wherein said lower drift tool issupported for rotational movement relative to said winding tool.
 10. Theapparatus of claim 9, wherein said lower drift tool includes a generallycylindrical drift tool body, and a plurality of drift blades extendingradially from said drift tool body for extending through the slots ofsaid stator stack.
 11. The apparatus of claim 10, including a stationaryguide member located in stationary relationship to said stator nest andpositioned between adjacent drift blades to guide said lower drift toolin rotating movement.
 12. The apparatus of claim 10, wherein said driftblades extend at an angle relative to a rotational axis of said lowerdrift tool.
 13. The apparatus of claim 6, wherein said winding tooldefines a generally cylindrical outer surface and said wire feedaperture comprises an opening formed in said outer surface.
 14. Anapparatus for forming field coils on a stator for a dynamo-electricmachine, said stator including a plurality of slots defined by statorteeth, said apparatus comprising: a stator nest for holding a statorstack; a winding tool extending through said stator nest for locatingwire in a stator stack held in said stator nest, said winding toolsupported for longitudinal movement and including a wire feed aperturefor feeding wire into slots of a stator stack supported in said statornest; an upper drift tool comprising a generally cylindrical drift toolbody, and a plurality of drift blades extending radially from said drifttool body for extending through the slots of said stator stack forengaging and forming wire located in the slots of said stator stackadjacent an upper end of said winding tool; and a lower drift toolsupported for longitudinal movement with said winding tool, said lowerdrift tool comprising a generally cylindrical drift tool body, and aplurality of drift blades extending radially from said drift tool bodyfor extending through the slots of said stator stack for engaging andforming wire located in the slots of said stator stack adjacent a lowerend of said winding tool.
 15. The apparatus of claim 14, including astationary guide member located in stationary relationship to saidstator nest and positioned between adjacent drift blades of said lowerdrift tool to guide said lower drift tool in rotating movement relativeto said stator nest.
 16. The apparatus of claim 14, wherein said lowerdrift tool is supported for rotational movement relative to said windingtool.